Some mobile devices, such as, for example, smartphones, personal pocket computers, personal digital assistants, tablets, and the like, incorporate a touchscreen, which is an electronic visual display that can detect the presence and/or location of a touch within the display. A touchscreen enables a user to interact directly with displayed content, providing an immersive user experience. For example, a user can slide a finger across the touchscreen to scroll a displayed screen content, document or webpage.
Various touchscreen technologies have been used, including, by way of example, capacitive touchscreen panels, which sense changes in capacitance caused by a finger, or other conductive device touching the panel. These touchscreens are capable of detecting the location of input gestures, such as single or multiple finger taps or drags. Some touchscreens are capable of detecting multiple simultaneous input touches, thus enabling more complex input gestures, including two-finger drags, two-finger taps, and pinch/expand (i.e., two fingers drawn together or apart on the touchscreen panel).
In addition, some mobile devices also include accelerometers that can be used to sense, for example, orientation, acceleration, vibration, shock, and the like. In the Apple iPhone device, an accelerometer is used for, inter cilia, sensing the display orientation, thus allowing a user to switch between landscape and portrait modes by simply rotating the device. Accelerometers are also used as another mechanism for a user to control a device. For example, accelerometers are sometimes used as input devices, allowing users to control the device by tilting it in the desired direction. This technique is used in the RotoView tilt-and-scroll system, which provides tilt-based navigation in hand held devices. See http://www.rotoview.com.
Using touchscreens and/or accelerometers, mobile devices enable users to view multi-page documents and other content. For example, the Apple iPhone device enables a user to view multi-page documents in Adobe PDF format, scrolling through a page using single-finger drags. When the end of a page is reached, scrolling continues to the next pages, and so on. When the beginning or end of the document is reached, the iPhone device pans the display such that the edge of the document (i.e., the beginning or end of the document) is displayed at or near the edge of the display. This effect is referred to herein as a rigid bouncing effect.